#include <side/trace.h>
#include <string.h>
-#include "tracer.h"
#include "rcu.h"
#include "list.h"
/* Top 8 bits reserved for kernel tracer use. */
-#define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000
-#define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000
+#if SIDE_BITS_PER_LONG == 64
+# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF00000000000000ULL
+# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x8000000000000000ULL
-/* Allow 2^24 tracer callbacks to be registered on an event. */
-#define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFF
+/* Allow 2^56 tracer references on an event. */
+# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFFFFFFFFFULL
+#else
+# define SIDE_EVENT_ENABLED_KERNEL_MASK 0xFF000000UL
+# define SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK 0x80000000UL
+
+/* Allow 2^24 tracer references on an event. */
+# define SIDE_EVENT_ENABLED_USER_MASK 0x00FFFFFFUL
+#endif
struct side_events_register_handle {
struct side_list_node node;
uint32_t nr_events;
};
+struct side_tracer_handle {
+ struct side_list_node node;
+ void (*cb)(enum side_tracer_notification notif,
+ struct side_event_description **events, uint32_t nr_events, void *priv);
+ void *priv;
+};
+
static struct side_rcu_gp_state rcu_gp;
/*
*/
static bool finalized;
-static pthread_mutex_t side_lock = PTHREAD_MUTEX_INITIALIZER;
+/*
+ * Recursive mutex to allow tracer callbacks to use the side API.
+ */
+static pthread_mutex_t side_lock = PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP;
-static DEFINE_SIDE_LIST_HEAD(side_list);
+static DEFINE_SIDE_LIST_HEAD(side_events_list);
+static DEFINE_SIDE_LIST_HEAD(side_tracer_list);
/*
* The empty callback has a NULL function callback pointer, which stops
* iteration on the array of callbacks immediately.
*/
-const struct side_callback side_empty_callback;
-
-void side_init(void) __attribute__((constructor));
-void side_exit(void) __attribute__((destructor));
+const struct side_callback side_empty_callback = { };
-void side_call(const struct side_event_description *desc, const struct side_arg_vec_description *sav_desc)
+void side_call(const struct side_event_description *desc, const struct side_arg_vec *side_arg_vec)
{
+ struct side_rcu_read_state rcu_read_state;
const struct side_callback *side_cb;
- unsigned int rcu_period;
- uint32_t enabled;
+ uintptr_t enabled;
if (side_unlikely(finalized))
return;
if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
// TODO: call kernel write.
}
- if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK)))
- return;
-
- //TODO: replace tracer_call by rcu iteration on list of registered callbacks
- tracer_call(desc, sav_desc, NULL);
-
- rcu_period = side_rcu_read_begin(&rcu_gp);
+ side_rcu_read_begin(&rcu_gp, &rcu_read_state);
for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call != NULL; side_cb++)
- side_cb->u.call(desc, sav_desc, side_cb->priv);
- side_rcu_read_end(&rcu_gp, rcu_period);
+ side_cb->u.call(desc, side_arg_vec, side_cb->priv);
+ side_rcu_read_end(&rcu_gp, &rcu_read_state);
}
void side_call_variadic(const struct side_event_description *desc,
- const struct side_arg_vec_description *sav_desc,
- const struct side_arg_dynamic_event_struct *var_struct)
+ const struct side_arg_vec *side_arg_vec,
+ const struct side_arg_dynamic_struct *var_struct)
{
+ struct side_rcu_read_state rcu_read_state;
const struct side_callback *side_cb;
- unsigned int rcu_period;
- uint32_t enabled;
+ uintptr_t enabled;
if (side_unlikely(finalized))
return;
if (side_unlikely(enabled & SIDE_EVENT_ENABLED_KERNEL_USER_EVENT_MASK)) {
// TODO: call kernel write.
}
- if (side_unlikely(!(enabled & SIDE_EVENT_ENABLED_USER_MASK)))
- return;
-
- //TODO: replace tracer_call by rcu iteration on list of registered callbacks
- tracer_call_variadic(desc, sav_desc, var_struct, NULL);
-
- rcu_period = side_rcu_read_begin(&rcu_gp);
+ side_rcu_read_begin(&rcu_gp, &rcu_read_state);
for (side_cb = side_rcu_dereference(desc->callbacks); side_cb->u.call_variadic != NULL; side_cb++)
- side_cb->u.call_variadic(desc, sav_desc, var_struct, side_cb->priv);
- side_rcu_read_end(&rcu_gp, rcu_period);
+ side_cb->u.call_variadic(desc, side_arg_vec, var_struct, side_cb->priv);
+ side_rcu_read_end(&rcu_gp, &rcu_read_state);
}
static
const struct side_callback *side_tracer_callback_lookup(
const struct side_event_description *desc,
- void (*call)(), void *priv)
+ void *call, void *priv)
{
const struct side_callback *cb;
for (cb = desc->callbacks; cb->u.call != NULL; cb++) {
- if (cb->u.call == call && cb->priv == priv)
+ if ((void *) cb->u.call == call && cb->priv == priv)
return cb;
}
return NULL;
static
int _side_tracer_callback_register(struct side_event_description *desc,
- void (*call)(), void *priv)
+ void *call, void *priv)
{
struct side_callback *old_cb, *new_cb;
int ret = SIDE_ERROR_OK;
return SIDE_ERROR_INVAL;
if (finalized)
return SIDE_ERROR_EXITING;
+ if (!initialized)
+ side_init();
pthread_mutex_lock(&side_lock);
- old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK;
- if (old_nr_cb == SIDE_EVENT_ENABLED_USER_MASK) {
+ old_nr_cb = desc->nr_callbacks;
+ if (old_nr_cb == UINT32_MAX) {
ret = SIDE_ERROR_INVAL;
goto unlock;
}
}
memcpy(new_cb, old_cb, old_nr_cb);
if (desc->flags & SIDE_EVENT_FLAG_VARIADIC)
- new_cb[old_nr_cb].u.call_variadic = call;
+ new_cb[old_nr_cb].u.call_variadic =
+ (side_tracer_callback_variadic_func) call;
else
- new_cb[old_nr_cb].u.call = call;
+ new_cb[old_nr_cb].u.call =
+ (side_tracer_callback_func) call;
new_cb[old_nr_cb].priv = priv;
side_rcu_assign_pointer(desc->callbacks, new_cb);
side_rcu_wait_grace_period(&rcu_gp);
if (old_nr_cb)
free(old_cb);
+ desc->nr_callbacks++;
/* Increment concurrently with kernel setting the top bits. */
- (void) __atomic_add_fetch(desc->enabled, 1, __ATOMIC_RELAXED);
+ if (!old_nr_cb)
+ (void) __atomic_add_fetch(desc->enabled, 1, __ATOMIC_RELAXED);
unlock:
pthread_mutex_unlock(&side_lock);
return ret;
}
int side_tracer_callback_register(struct side_event_description *desc,
- void (*call)(const struct side_event_description *desc,
- const struct side_arg_vec_description *sav_desc,
- void *priv),
+ side_tracer_callback_func call,
void *priv)
{
if (desc->flags & SIDE_EVENT_FLAG_VARIADIC)
return SIDE_ERROR_INVAL;
- return _side_tracer_callback_register(desc, call, priv);
+ return _side_tracer_callback_register(desc, (void *) call, priv);
}
int side_tracer_callback_variadic_register(struct side_event_description *desc,
- void (*call_variadic)(const struct side_event_description *desc,
- const struct side_arg_vec_description *sav_desc,
- const struct side_arg_dynamic_event_struct *var_struct,
- void *priv),
+ side_tracer_callback_variadic_func call_variadic,
void *priv)
{
if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))
return SIDE_ERROR_INVAL;
- return _side_tracer_callback_register(desc, call_variadic, priv);
+ return _side_tracer_callback_register(desc, (void *) call_variadic, priv);
}
-int _side_tracer_callback_unregister(struct side_event_description *desc,
- void (*call)(), void *priv)
+static int _side_tracer_callback_unregister(struct side_event_description *desc,
+ void *call, void *priv)
{
struct side_callback *old_cb, *new_cb;
const struct side_callback *cb_pos;
return SIDE_ERROR_INVAL;
if (finalized)
return SIDE_ERROR_EXITING;
+ if (!initialized)
+ side_init();
pthread_mutex_lock(&side_lock);
cb_pos = side_tracer_callback_lookup(desc, call, priv);
if (!cb_pos) {
ret = SIDE_ERROR_NOENT;
goto unlock;
}
- old_nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK;
+ old_nr_cb = desc->nr_callbacks;
old_cb = (struct side_callback *) desc->callbacks;
if (old_nr_cb == 1) {
new_cb = (struct side_callback *) &side_empty_callback;
side_rcu_assign_pointer(desc->callbacks, new_cb);
side_rcu_wait_grace_period(&rcu_gp);
free(old_cb);
+ desc->nr_callbacks--;
/* Decrement concurrently with kernel setting the top bits. */
- (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
+ if (old_nr_cb == 1)
+ (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
unlock:
pthread_mutex_unlock(&side_lock);
return ret;
}
int side_tracer_callback_unregister(struct side_event_description *desc,
- void (*call)(const struct side_event_description *desc,
- const struct side_arg_vec_description *sav_desc,
- void *priv),
+ side_tracer_callback_func call,
void *priv)
{
if (desc->flags & SIDE_EVENT_FLAG_VARIADIC)
return SIDE_ERROR_INVAL;
- return _side_tracer_callback_unregister(desc, call, priv);
+ return _side_tracer_callback_unregister(desc, (void *) call, priv);
}
int side_tracer_callback_variadic_unregister(struct side_event_description *desc,
- void (*call_variadic)(const struct side_event_description *desc,
- const struct side_arg_vec_description *sav_desc,
- const struct side_arg_dynamic_event_struct *var_struct,
- void *priv),
+ side_tracer_callback_variadic_func call_variadic,
void *priv)
{
if (!(desc->flags & SIDE_EVENT_FLAG_VARIADIC))
return SIDE_ERROR_INVAL;
- return _side_tracer_callback_unregister(desc, call_variadic, priv);
+ return _side_tracer_callback_unregister(desc, (void *) call_variadic, priv);
}
struct side_events_register_handle *side_events_register(struct side_event_description **events, uint32_t nr_events)
{
- struct side_events_register_handle *handle = NULL;
+ struct side_events_register_handle *events_handle = NULL;
+ struct side_tracer_handle *tracer_handle;
if (finalized)
return NULL;
- handle = calloc(1, sizeof(struct side_events_register_handle));
- if (!handle)
+ if (!initialized)
+ side_init();
+ events_handle = (struct side_events_register_handle *)
+ calloc(1, sizeof(struct side_events_register_handle));
+ if (!events_handle)
return NULL;
+ events_handle->events = events;
+ events_handle->nr_events = nr_events;
+
pthread_mutex_lock(&side_lock);
- handle->events = events;
- handle->nr_events = nr_events;
- side_list_insert_node_tail(&side_list, &handle->node);
+ side_list_insert_node_tail(&side_events_list, &events_handle->node);
+ side_list_for_each_entry(tracer_handle, &side_tracer_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS,
+ events, nr_events, tracer_handle->priv);
+ }
pthread_mutex_unlock(&side_lock);
//TODO: call event batch register ioctl
- return handle;
+ return events_handle;
}
static
void side_event_remove_callbacks(struct side_event_description *desc)
{
- uint32_t nr_cb = *desc->enabled & SIDE_EVENT_ENABLED_USER_MASK;
+ uint32_t nr_cb = desc->nr_callbacks;
struct side_callback *old_cb;
if (!nr_cb)
return;
old_cb = (struct side_callback *) desc->callbacks;
+ (void) __atomic_add_fetch(desc->enabled, -1, __ATOMIC_RELAXED);
/*
* Setting the state back to 0 cb and empty callbacks out of
* caution. This should not matter because instrumentation is
* unreachable.
*/
- (void) __atomic_add_fetch(desc->enabled, -nr_cb, __ATOMIC_RELAXED);
+ desc->nr_callbacks = 0;
side_rcu_assign_pointer(desc->callbacks, &side_empty_callback);
/*
* No need to wait for grace period because instrumentation is
* Unregister event handle. At this point, all side events in that
* handle should be unreachable.
*/
-void side_events_unregister(struct side_events_register_handle *handle)
+void side_events_unregister(struct side_events_register_handle *events_handle)
{
+ struct side_tracer_handle *tracer_handle;
uint32_t i;
+ if (!events_handle)
+ return;
if (finalized)
return;
+ if (!initialized)
+ side_init();
pthread_mutex_lock(&side_lock);
- side_list_remove_node(&handle->node);
- for (i = 0; i < handle->nr_events; i++) {
- struct side_event_description *event = handle->events[i];
+ side_list_remove_node(&events_handle->node);
+ side_list_for_each_entry(tracer_handle, &side_tracer_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS,
+ events_handle->events, events_handle->nr_events,
+ tracer_handle->priv);
+ }
+ for (i = 0; i < events_handle->nr_events; i++) {
+ struct side_event_description *event = events_handle->events[i];
/* Skip NULL pointers */
if (!event)
}
pthread_mutex_unlock(&side_lock);
//TODO: call event batch unregister ioctl
- free(handle);
+ free(events_handle);
+}
+
+struct side_tracer_handle *side_tracer_event_notification_register(
+ void (*cb)(enum side_tracer_notification notif,
+ struct side_event_description **events, uint32_t nr_events, void *priv),
+ void *priv)
+{
+ struct side_tracer_handle *tracer_handle;
+ struct side_events_register_handle *events_handle;
+
+ if (finalized)
+ return NULL;
+ if (!initialized)
+ side_init();
+ tracer_handle = (struct side_tracer_handle *)
+ calloc(1, sizeof(struct side_tracer_handle));
+ if (!tracer_handle)
+ return NULL;
+ pthread_mutex_lock(&side_lock);
+ tracer_handle->cb = cb;
+ tracer_handle->priv = priv;
+ side_list_insert_node_tail(&side_tracer_list, &tracer_handle->node);
+ side_list_for_each_entry(events_handle, &side_events_list, node) {
+ cb(SIDE_TRACER_NOTIFICATION_INSERT_EVENTS,
+ events_handle->events, events_handle->nr_events, priv);
+ }
+ pthread_mutex_unlock(&side_lock);
+ return tracer_handle;
+}
+
+void side_tracer_event_notification_unregister(struct side_tracer_handle *tracer_handle)
+{
+ struct side_events_register_handle *events_handle;
+
+ if (finalized)
+ return;
+ if (!initialized)
+ side_init();
+ pthread_mutex_lock(&side_lock);
+ side_list_for_each_entry(events_handle, &side_events_list, node) {
+ tracer_handle->cb(SIDE_TRACER_NOTIFICATION_REMOVE_EVENTS,
+ events_handle->events, events_handle->nr_events,
+ tracer_handle->priv);
+ }
+ side_list_remove_node(&tracer_handle->node);
+ pthread_mutex_unlock(&side_lock);
}
void side_init(void)
initialized = true;
}
+/*
+ * side_exit() is executed from a library destructor. It can be called
+ * explicitly at application exit as well. Concurrent side API use is
+ * not expected at that point.
+ */
void side_exit(void)
{
struct side_events_register_handle *handle, *tmp;
if (finalized)
return;
- side_rcu_gp_exit(&rcu_gp);
- side_list_for_each_entry_safe(handle, tmp, &side_list, node)
+ side_list_for_each_entry_safe(handle, tmp, &side_events_list, node)
side_events_unregister(handle);
+ side_rcu_gp_exit(&rcu_gp);
finalized = true;
}